Manuela Oliveira
@ipma.pt
DivRP
RESEARCH, TEACHING, or OTHER INTERESTS
Strategy and Management, Control and Optimization, Management Science and Operations Research, Information Systems and Management
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Paula Ramos, R. Varandas, I. L. Conceição, A. Grade, M. M. Oliveira, G. Alexandre-Pires, and F. Rosa
Springer Science and Business Media LLC
Mafalda Rangel, Cristina Pita, Manuela Maria de Oliveira, Maria Helena Guimarães, Rita Rainha, Carlos Sonderblohm, Pedro Monteiro, Frederico Oliveira, Marta Ballesteros, Jorge M.S. Gonçalves,et al.
Elsevier BV
Manuela M. Oliveira, Ana S. Camanho, John B. Walden, Vera L. Miguéis, Nuno B. Ferreira, and Miguel B. Gaspar
Elsevier BV
Manuela M. Oliveira, Ana S. Camanho, John B. Walden, and Miguel B. Gaspar
Oxford University Press (OUP)
Nuno Barbosa Ferreira and Manuela M. Oliveira
Informa UK Limited
ABSTRACT This study aimed to assess the technical efficiency (TE) of individual companies and their respective sectors that are traded on the Portuguese stock market. We accomplished this by combining the internal input variables (e.g., ‘market value and return’) with exogenous variables (e.g., ‘interest income’, ‘depreciation’, ‘cost of goods’, ‘employees’ and ‘net sales’) into a Stochastic Frontier Analysis (SFA) model. The TE of the PSI-20 (Portuguese Stock Index) was estimated using factors that affect efficiency variability. The main advantage of using the SFA approach is its potential to discriminate between measurement error and systematic inefficiencies in the estimation process. The results demonstrated that TE is higher for enterprises in the industrial, construction and distribution sectors, whereas the commercial banking sector has the lowest TE scores. The ‘employees’ and ‘depreciation’ are the variables which most contribute to stock market inefficiency.
J.H. Martins, A.S. Camanho, M.M. Oliveira, and M.B. Gaspar
Wiley
AbstractThis paper presents a management model developed to promote the sustainability of artisanal fisheries, considering socioeconomic and environmental dimensions. The management of artisanal fisheries faces many challenges, including the lack of appropriate tools to support policy makers and stakeholders in the decision‐making process. The model presented in this study is based on system dynamics and allows the simulation of the behavior of the artisanal dredge fishery on the south coast of Portugal, including four main species and two fleets. Two scenarios were simulated to assess the impact of regulatory measures on the system sustainability: scenario 1 simulated a permanent reduction of fishing effort, returning an improvement of biologic and economic sustainability; scenario 2 simulated the closure of one species for a period of one year to allow its recovery. It was found that although the revenue of fisheries decreases in that year, the system is able to return to the average levels of revenue three years after the closure. The study aimed to guide decision makers in the selection of the most appropriate measures toward the preservation of marine ecosystems and socioeconomic stability of fishing communities. The developed system dynamics model, combining available data with knowledge of fisheries experts, proved to be a useful scientific tool to identify management policies and organizational structures leading to greater success. This technique can be applied to the study of other fishery systems worldwide.
M.M. Oliveira, A.S. Camanho, and M.B. Gaspar
Elsevier BV
M.M. Oliveira, A.S. Camanho, and M.B. Gaspar
Elsevier BV
Lucía García-Flórez, Jesús Morales, Miguel B. Gaspar, David Castilla, Estanis Mugerza, Patrick Berthou, Laura García de la Fuente, Manuela Oliveira, Oscar Moreno, Juan José García del Hoyo,et al.
Elsevier BV
M. M. Oliveira, A. S. Camanho, and M. B. Gaspar
Oxford University Press (OUP)
Abstract Oliveira, M. M., Camanho, A. S., and Gaspar, M. B. 2013. The influence of catch quotas on the productivity of the Portuguese bivalve dredge fleet. – ICES Journal of Marine Science, 70: . Among the Portuguese artisanal fishing fleets, the bivalve dredge fleet is one of the most profitable. In the last decade, after the implementation of a quotas system, the management of this fishery has been largely focused on adjusting catch to the conservation status of the resources exploited. The present work aims to understand how changes in the amount of quota attributed to each vessel each year and shifts in the quota regime affected vessel productivity. Boostrapped Malmquist indices, complemented with an efficiency assessment using a directional distance function, were used to quantify productivity changes between 1999 and 2011 for the fleets operating in two areas along the Portuguese coast (northwest and southwest). The results showed that the implementation of a weekly quota, as opposed to a daily quota, led to a significant improvement in productivity. This was mainly due to the decrease in fishing days and fuel consumption. It is predicted that the implementation of weekly quotas in the south area would lead to an overall reduction of about 12% in fishing days and fuel consumption, even though the variation in fuel consumption may be affected by the status of the resources. The results achieved provide important insights for future management actions and showed the potential advantages of applying this type of management to other fisheries worldwide, mainly those using active gear.
Manuela M. Oliveira, Ana S. Camanho, and Miguel B. Gaspar
Oxford University Press (OUP)
AbstractOliveira, M. M., Camanho, A. S., and Gaspar, M. B. 2010. Technical and economic efficiency analysis of the Portuguese artisanal dredge fleet. – ICES Journal of Marine Science, 67: 1811–1821. An efficiency analysis of the commercial dredge fleet operating along the south coast of Portugal between 2005 and 2007 sought to determine the efficiency of the vessels using data envelopment analysis models, considering fixed inputs (vessel power, length, tonnage, and an indicator of stock biomass) and a variable input (number of days at sea). The annual quota per vessel was also included in the model as a contextual factor. In the technical-efficiency (TE) analysis, outputs were defined by the catch weight for each of the three target species (bivalves). Using price data for each species in the wholesale market, revenue efficiency was also estimated to complement the TE analysis. The advantage of the approach lies in the ability to separate technical aspects from allocative aspects in the efficiency assessment, allowing two-dimensional graphic representation of vessel performance. The procedure allows the identification of benchmark vessels, which maximized the catch weight of the species landed, given their inputs, as well as the vessels that selected the appropriate target species to maximize the revenue of the fishing activity, given output prices. The approach also allowed the specification of targets for inefficient vessels that correspond to the catch by species, permitting revenue maximization from fishing.
M.M. Oliveira, M.B. Gaspar, J.P. Paixão, and A.S. Camanho
Elsevier BV